package com.by.auth;


import com.auth0.jwt.JWT;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.TokenExpiredException;
import com.auth0.jwt.interfaces.Claim;
import com.auth0.jwt.interfaces.DecodedJWT;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;

@Component
public class TokenTemplate {
    /**
     * 密钥
     */
    @Value("${token.secret}")
    String secret; //密钥
    /**
     * token有效时间  单位是s
     */
    @Value("${token.validTime}")
    long validTime;

    private final long DEFAULT_TIME = 30 * 60 * 1000;  //默认30分钟有效期

    /**
     * 生成token
     *
     * @param payload 用户信息
     * @return token字符串
     */
    public String generateToken(Map payload) {
        String token = JWT.create()
                .withHeader(getHeader())
                .withPayload(payload)
                .withExpiresAt(getValidDate())// 给token设置有效期
                .sign(Algorithm.HMAC256(getSecret()));
        return token;
    }

    /**
     * 验证token
     *
     * @param token
     * @return
     */
    public ValidResult validate(String token) {
        if (null == token || "".equals(token))
            return new ValidResult(0, "token为空", null);
        //不为空 验证
        DecodedJWT decodedJWT = null;

        try {
            decodedJWT = JWT.require(Algorithm.HMAC256(secret))
                    .build()
                    .verify(token);
        } catch (TokenExpiredException e) {
            return new ValidResult(0, "token已过期", null);
        } catch (Exception e) {
            return new ValidResult(1, "token无效", null);
        }
        //验证通过
        Map<String, Claim> map = decodedJWT.getClaims();
        return new ValidResult(2, "验证成功", convert(map));
    }


    /**
     * 刷新token
     * @param token
     * @return
     */
    public String refreshToken(String token){
        //验证token
        ValidResult result=validate(token);
        if(result.getCode()==1){//token无效
            return null;
        }else if(result.getCode()==0){
            //说明过期
            DecodedJWT decodedJWT = JWT.decode(token);
            //获取用户信息
            Map<String, Claim> map = decodedJWT.getClaims();
            //生成新的token
            return generateToken(convert(map));
        }

        //token正常时刷新
        Map map=result.getUser();
        //生成新的token
        return generateToken(map);
    }


    Map<String, String> convert(Map<String, Claim> map) {
        Map<String, String> tmp = new HashMap<>();
        //遍历map
        map.forEach((key, value) -> {
            tmp.put(key, value.asString());
        });
        return tmp;
    }

    /*
   获取30s后的日期
    */
    Date getValidDate() {
        long time = System.currentTimeMillis() + getValidTime();
        Date now = new Date(time);
        return now;
    }

    /**
     * 头部
     *
     * @return
     */
    Map getHeader() {
        Map map = new HashMap();
        map.put("typ", "JWT");
        map.put("alg", "HS256");
        return map;
    }


    public String getSecret() {
        if (null == secret) {
            secret = UUID.randomUUID().toString(); //随机产生一个36位字符串
        }
        return secret;
    }

    public void setSecret(String secret) {
        this.secret = secret;
    }

    public long getValidTime() {
        if (validTime == 0) {
            //初始化
            validTime = DEFAULT_TIME;
        }
        return validTime;
    }

    public void setValidTime(long validTime) {
        this.validTime = validTime;
    }
}
